It makes sense comparing Denon AVR-X3500H vs Denon AVR-X4400H because they both are able to give some premium features.
A significant difference between the receivers in the number of channels, Denon AVR-X3500H has 7.2 versus 11.2 for Denon AVR-X4400H. Regarding power, then AVR-X3500H has such a W/Ohm ratio - 105/8, 135/6 when AVR-X4400H has a power of 125/8, 165/6. The THD is the same and is 0.05%.
Characteristics of digital to analog converter (DAC) are different, AKM 192 KHz/32-bit for AVR-X3500H and AK4458 384 KHz/32-bit for the AVR-X4400H. Both the AVR-X3500H and the AVR-X4400H support Bi-amping. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
WI-FI modules have the same characteristics: 2.4/5GHz. Rivals from our review have Bluetooth support. The Apple Music service is implemented on considered devices: AirPlay, AirPlay 2. Spotify can be used on each receiver. The AVR-X3500H can work with the audio stream from Deezer, TIDAL, Pandora, TuneIn Radio, and the AVR-X4400H can receive a content from Deezer, TIDAL, Pandora, Napster, SiriusXM, TuneIn Radio, iHeart Radio, Sound Cloud. Compared AV receivers retain the quality of 4K/60Hz signal when transmitting from a source to a TV or projector. HDMI signal transmission in standby mode is implemented in each of the devices. Both rivals can scale the resolution of the incoming HDMI signal. The HDR standard - Dolby Vision is supported by these receivers.
Each receiver has 8/3 HDMI inputs/outputs. The HDMI Audio Return Channel (ARC) feature supports both devices. The HDMI eARC is available only on the AVR-X4400H. The Consumer Electronics Control (CEC) feature is present in most modern AV receivers and the models in our comparison are no exception. Both models support the standard HDCP 2.2. These compared receivers have a built-in phono stage for connecting a vinyl player.
The AVR-X3500H supports 2 Multi-room zones, versus 3 for the AVR-X4400H. Supported voice control technologies are identical - Amazon Alexa, Google Assistant, Siri, Josh.AI. It is also worth noting that the ECO mode is presented in each of the receivers. Both AVR-X3500H and AVR-X4400H can be configured using the Setup assistant.
Both devices have support for Dolby Atmos multichannel audio format. The surround sound technology DTS:X is supported by devices under review.